Paper trimmer



- Sept. 13, 1932.

w. p. FORBES 1,876,902

PAPER TRIMMER Filed June 1. 1929 mlmlIllllllllllllllIlllllllIlllllllllllllllllllllllll F164- mja 5 INVENTOR. v Aim/.722? p. FORBES,

ATTORNEYS.

Patented Sept. 13, 1932 I v UNITED STATES.

WALTER D. FORBES, OF SAN FRANCISCO, CALIFORNIA PAPER TRIMMER i Applieation filed'J'une 1, 1929. Serial No. 367,677.

This invention relates to paper trimmers or cutters, especially the type used for trimming photographic and other prints, though the Invention may be incorporated in the larger paper and cardboard cutters used by printers, paper houses, and others, and also infcutters of the same general type used for In the drawing accompanying this application Fig, 1 is a perspective view of a cutter or trimming board made in accordance with my invention and provided with two blades or knives each with cutting edges formed to follow an angular line along a cylindrical surface of revolution operating along two adjacent edges of the board.

Fig. 2 is an enlarged cross section of Fig. 1 takenalong the line 22 thereof.

Fig, 3. is an enlarged plan view of the corner of the board showing the two knives geared together for simultaneous action and each extending slightly beyond the corner in overlapping arrangement. a

Fig. 4 is a plan view of a. trimming board showing a modified construction employing two straight guillotine form of knives.

, Fig. 5 is a cross section of Fig. 4 taken along the line 55 thereof showing the overlapping of the knives at the corner of the board and the mounting of the knives for vertical slid mg. 7

In the construction shown in Figs. 1 to 3 the base or board proper on which the sheet of paper or other material is laid for trimming isdesignated 1 and it is shown marked off with indicating lines 2 to assist positioning the sheet thereon.

Along the two cutting edges of the board are fixed knives 3-3 cooperatingwithrevolv i H 'ingknives 4-4 for trimming two margins of the sheet. The revolving knives are pivotally mounted in bearings 56 secured to the board, and are preferably formed from flat bar steel with ends 7 bent at right angles and from which short trunnions '89 project to serve as axles for the knives.

The knives may be helicoidal blades as in i a common lawn mower, but in the figures I show the run of the blades each as a straight flat bar arranged at an angle to the axis of ro-, tation and with the cutting edge ground'off to follow the surface of a cylinder whose axis is that of the trunnions 89, so that th t. 1 1

ting edge itself follows what may be termed a helicoidal line though the body of theblade} is a flat bar. This makes for simplicity and cheapness of construction. Y

The knives are geared together at their in-- ner ends by means of miter gears 10 secure to trunnions 9 .and the trunnions extend beyond the gears into the bearings 6. Y The gears are meshed in a manner to time the knives,- one slightly in advance of the other, so that their inner ends which overlap or extend slightly beyond thecorner of the board as indicated'at 11 will not interfere. In Fig.1 knife 4' is'shown as already descended below the corner and knife 4 about 6 to follow. I v

To operate the knives any well known form of power application as used in cuttersmay' be used, though in small boards I provide-a imple lever 12 secured to the trunnion at the outer'end of one of the knives, and which lever is revolved in directionof the arrows. to v rotateboth knives and thus to simultaneously; out both adjacent margins of a sheet laid on the board and projecting beyond the fixed knives 33. It being understood that lever 12 is rotated to the right far enough to 'lift' both knives clear of the inner corner of the board so that the sheet canvbe projected at I h;

its inner corner beyond the fixed knives.

In sharpening knives 44 they will be revolved on their trunnion axes and ground off on a revolving wheel traveling longitudinally of the knife-and this will of course reduce their effective diameters slightly, so that an 100 adjustment must be made either by moving the fixed knives 33 slightly outward, or by moving the revolving knives slightly inward, and I therefore show bearings 5 as inwardly adjustable by means of screws 13 and bear ings 6 are provided with threaded extensions 6 which may be clamped against fixed brackets 6 carried on a plate 1 1 rigidly secured to the board. It will be evident that many other forms of adjustment may be provided to accomplish the same purpose.

In the modified form ofthe invention shown in Figs. 4 and 5 employing the guillotine form knives 16 and guillotine knives 17-48, the latter'being slidably mounted on short rods 19 guided in slotted vertical tubular guides 20; and aresimultaneously actuated by means of:rotatable:shafts"21-22;geared together at 23: and provided: with: pinions 24: extending through slots inthe tubular guidesQO and engagingmck teeth225 cut: in rods-.19,- all in a manner so that upon'revolving the shaftsby any means-lsuchias'by. the hand lever 26 or by power appliedf-inany desired manner,thepiniOIlSiWIlll simultaneously slide the rods 19 downward-land operate :both knives.

Thestraight-knives of this showing also o 'erlapat the inner corner of the board as indicated in the figures and are preferably set at an angle as shown for blade 17 in Fig. 5,

also with the inner end of oneblade lower them the other so that the overlapping arrangement of the blades at: the corner: may be secured and which is adesirable feature in avoiding the'otherwiseextreme nicety of adjustment at this'point to insure a clean cut corner.

In considering my' invention as above set forth, it shouldbenoted that while-L show a I trimming board or base plate with two simultanoously 'actuated knives lying along adja-' cent edg'es of th'eboards; it'ismanifest that the=invention is not limited to two knives, as I additional knives may be usedatother edges of the board, also that it is immaterial whether the board'berectangular or any other multisided sh'ape:

I claim:

1'. A trimmer for sheet material comprising a base "plate upon'which the sheet is laid including fixed cutting" edges, a plurality of trimming knives operatively arranged respectively along the'edge's of said base plate for'trim'ming themargins-of the sheet thereagainstgthe cutting'edges of said knives extending intoverlapping arrangement with respectto azcorn'erof thebase plate, and means for operating said-knives;-

2. Actrimmer fon sheet material comprisingta base'plate upon-Which the sheet is-laid including fixedi cutting edges, a plurality of trimmingv knives: operatively arranged respectively. along'the edges of said base plate for trimming the margins of the sheet thereagainst, said knives extending in overlapping arrangement with respect to a corner of the base plate, and means for operating said knives comprising power application means at the end of one knife, and power transmitting mechanism between the opposite end of the knife, and the next adjacent knife.

3. A trimmer for sheet material comprising a rectangular base plate upon which the sheet is laid including fixed cutting edges and a pair of trimming knives operatively arranged'respectlvely along diverglng edges of of knife the board is desi 'nated 15, fixed the sheet thereagalnst, said knlves being set said base plate for trimming the margins of said corner, and means for operatingsaid knives.

4. A trimmer for sheet material comprlsing a base plate upon which the sheet is laid' including fixed cutting edges and a plurality of trimming knives operatively arranged respectively along the edges of said base plate for trimming the margins of the sheet thereagainst, said knives being formed without tingedges extending at an angle along a cylindrical surface of revolution, and support= ed on axes for revolving against said base plate, means on one knife for revolving the same, and transmission means connecting the knives together for simultaneous revolution;

5. YA trimmer for sheet material comprising a base plate upon which the sheetis laid, a knife provided with a cutting edge extending along an edge of said' base plate and formed to follow an angular line along a cylindrical surface of revolution, andme'ans" pivotally mounting the knife whereby itmay' be revolved against said edge,.the body'of said knife comprising a substantially straight fiat bar extendingat an angle to the'axis of ting edges extending at an angle along. a

cylindrical surface of revolution, and supported on axes for revolvlng agalnst sald base plate, and means for applying power to oneof said knives, and gear means operatively connecting the knives together.

7. In a structure as specified in claim 6, bearings in which said knives are revolvable secured to the base plat-e and means for adjusting said bearings to and from'said base plate. r

8, A trimmer for sheet materlal' comprising a base plate upon which the sheet is laid including fixed cutting edges and a plurality of trimming knives operatively arranged respectively along the edges of said base plate for trimming the marglns of the sheet thereagainst, said knives being formed with cutting edges extending at an angle along a cylindrical surface for revolution, and supported on axes for revolving against said base plate, means for applying power to oneof said knives, gear means operatively connecting the'knives together and means whereby the axes of said knives and base are relatively adjustable.

WALTER D. FORBES. 

